Monday, February 22, 2016

Can Beer Save the Bay?

Standing directly above the 150,000-gallon aeration basin of Ommegang’s wastewater treatment plant does bring to mind the smell of skunked beer. It is the destination for a pipe that carries all the production waste from the brewery—municipal and human waste is handled differently. Like a miracle in reverse, this is where the leftovers of an alcoholic beverage are turned back into water.

While yeast is fundamental to brewing beer, different microorganisms play a central role in breaking down Ommegang’s liquid waste. The process removes almost all the nitrogen and phosphorus from the water leaving the plant, keeping excess nutrients out of the Susquehanna River and the Chesapeake Bay.

The fermentation that makes beer and other alcoholic beverages is an anaerobic process, meaning it has to occur in the absence of oxygen. The waste process, however, is aerobic. The large blowers deliver oxygen to an activated sludge made of living microorganisms. The sludge takes about eight days to cycle through the aeration basin’s membrane bioreactor that filters the wastewater.

The sludge is mostly bacteria but also tiny animals like rotifers and nematodes. As Poliseno describes it, he could be describing cattle rotated on fields of grass.

“All those hungry organisms will be brought right back to where the feed is so they can break down even faster, because they'll be super hungry at that point,” Poliseno says.
As the bacteria eat, they grow and reproduce. The excess sludge is pressed dry and harvested as a valuable biomass that farmers spread on their fields.

So, all the nutrients are sequestered into the sludge, which is spread on farm fields where it will wash into the bay, the same as chickenshit. Which is fine, as long as the amount used is not more than the soil can hold.